linux/init, branch v6.15

init: remove unused CONFIG_CC_CAN_LINK_STATIC

2025-05-12T06:03:46Z

This is a leftover from commit 98e20e5e13d2 ("bpfilter: remove bpfilter"). Signed-off-by: Masahiro Yamada

rust: clean Rust 1.88.0's `unnecessary_transmutes` lint

2025-05-06T22:11:47Z

Starting with Rust 1.88.0 (expected 2025-06-26) [1][2], `rustc` may introduce a new lint that catches unnecessary transmutes, e.g.: error: unnecessary transmute --> rust/uapi/uapi_generated.rs:23242:18 | 23242 | unsafe { ::core::mem::transmute(self._bitfield_1.get(0usize, 1u8) as u8) } | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace this with: `(self._bitfield_1.get(0usize, 1u8) as u8 == 1)` | = note: `-D unnecessary-transmutes` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(unnecessary_transmutes)]` There are a lot of them (at least 300), but luckily they are all in `bindgen`-generated code. Thus clean all up by allowing it there. Since unknown lints trigger a lint itself in older compilers, do it conditionally so that we can keep the `unknown_lints` lint enabled. Cc: stable@vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs). Link: https://github.com/rust-lang/rust/pull/136083 [1] Link: https://github.com/rust-lang/rust/issues/136067 [2] Reviewed-by: Alice Ryhl Link: https://lore.kernel.org/r/20250502140237.1659624-4-ojeda@kernel.org Signed-off-by: Miguel Ojeda

Kconfig: switch CONFIG_SYSFS_SYCALL default to n

2025-04-15T08:28:35Z

This odd system call will be removed in the future. Let's decouple it from CONFIG_EXPERT and switch the default to n as a first step. Link: https://lore.kernel.org/20250415-dezimieren-wertpapier-9fd18a211a41@brauner Signed-off-by: Christian Brauner

Merge tag 'sched-urgent-2025-04-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2025-04-06T17:44:58Z

Pull scheduler fixes from Ingo Molnar: - Fix a nonsensical Kconfig combination - Remove an unnecessary rseq-notification * tag 'sched-urgent-2025-04-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: rseq: Eliminate useless task_work on execve sched/isolation: Make CONFIG_CPU_ISOLATION depend on CONFIG_SMP

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rmk/linux

2025-04-03T19:21:44Z

Pull ARM and clkdev updates from Russell King: - Simplify ARM_MMU_KEEP usage - Add Rust support for ARM architecture version 7 - Align IPIs reported in /proc/interrupts - require linker to support KEEP within OVERLAY - add KEEP() for ARM vectors - add __printf() attribute for clkdev functions * tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rmk/linux: ARM: 9445/1: clkdev: Mark some functions with __printf() attribute ARM: 9444/1: add KEEP() keyword to ARM_VECTORS ARM: 9443/1: Require linker to support KEEP within OVERLAY for DCE ARM: 9442/1: smp: Fix IPI alignment in /proc/interrupts ARM: 9441/1: rust: Enable Rust support for ARMv7 ARM: 9439/1: arm32: simplify ARM_MMU_KEEP usage

sched/isolation: Make CONFIG_CPU_ISOLATION depend on CONFIG_SMP

2025-04-03T11:08:04Z

kernel/sched/isolation.c obviously makes no sense without CONFIG_SMP, but the Kconfig entry we have right now: config CPU_ISOLATION bool "CPU isolation" depends on SMP || COMPILE_TEST allows the creation of pointless .config's which cause build failures. Reported-by: kernel test robot Signed-off-by: Oleg Nesterov Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20250330134955.GA7910@redhat.com Closes: https://lore.kernel.org/oe-kbuild-all/202503260646.lrUqD3j5-lkp@intel.com/

mseal sysmap: kernel config and header change

2025-04-01T22:17:14Z

Patch series "mseal system mappings", v9. As discussed during mseal() upstream process [1], mseal() protects the VMAs of a given virtual memory range against modifications, such as the read/write (RW) and no-execute (NX) bits. For complete descriptions of memory sealing, please see mseal.rst [2]. The mseal() is useful to mitigate memory corruption issues where a corrupted pointer is passed to a memory management system. For example, such an attacker primitive can break control-flow integrity guarantees since read-only memory that is supposed to be trusted can become writable or .text pages can get remapped. The system mappings are readonly only, memory sealing can protect them from ever changing to writable or unmmap/remapped as different attributes. System mappings such as vdso, vvar, vvar_vclock, vectors (arm compat-mode), sigpage (arm compat-mode), are created by the kernel during program initialization, and could be sealed after creation. Unlike the aforementioned mappings, the uprobe mapping is not established during program startup. However, its lifetime is the same as the process's lifetime [3]. It could be sealed from creation. The vsyscall on x86-64 uses a special address (0xffffffffff600000), which is outside the mm managed range. This means mprotect, munmap, and mremap won't work on the vsyscall. Since sealing doesn't enhance the vsyscall's security, it is skipped in this patch. If we ever seal the vsyscall, it is probably only for decorative purpose, i.e. showing the 'sl' flag in the /proc/pid/smaps. For this patch, it is ignored. It is important to note that the CHECKPOINT_RESTORE feature (CRIU) may alter the system mappings during restore operations. UML(User Mode Linux) and gVisor, rr are also known to change the vdso/vvar mappings. Consequently, this feature cannot be universally enabled across all systems. As such, CONFIG_MSEAL_SYSTEM_MAPPINGS is disabled by default. To support mseal of system mappings, architectures must define CONFIG_ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS and update their special mappings calls to pass mseal flag. Additionally, architectures must confirm they do not unmap/remap system mappings during the process lifetime. The existence of this flag for an architecture implies that it does not require the remapping of thest system mappings during process lifetime, so sealing these mappings is safe from a kernel perspective. This version covers x86-64 and arm64 archiecture as minimum viable feature. While no specific CPU hardware features are required for enable this feature on an archiecture, memory sealing requires a 64-bit kernel. Other architectures can choose whether or not to adopt this feature. Currently, I'm not aware of any instances in the kernel code that actively munmap/mremap a system mapping without a request from userspace. The PPC does call munmap when _install_special_mapping fails for vdso; however, it's uncertain if this will ever fail for PPC - this needs to be investigated by PPC in the future [4]. The UML kernel can add this support when KUnit tests require it [5]. In this version, we've improved the handling of system mapping sealing from previous versions, instead of modifying the _install_special_mapping function itself, which would affect all architectures, we now call _install_special_mapping with a sealing flag only within the specific architecture that requires it. This targeted approach offers two key advantages: 1) It limits the code change's impact to the necessary architectures, and 2) It aligns with the software architecture by keeping the core memory management within the mm layer, while delegating the decision of sealing system mappings to the individual architecture, which is particularly relevant since 32-bit architectures never require sealing. Prior to this patch series, we explored sealing special mappings from userspace using glibc's dynamic linker. This approach revealed several issues: - The PT_LOAD header may report an incorrect length for vdso, (smaller than its actual size). The dynamic linker, which relies on PT_LOAD information to determine mapping size, would then split and partially seal the vdso mapping. Since each architecture has its own vdso/vvar code, fixing this in the kernel would require going through each archiecture. Our initial goal was to enable sealing readonly mappings, e.g. .text, across all architectures, sealing vdso from kernel since creation appears to be simpler than sealing vdso at glibc. - The [vvar] mapping header only contains address information, not length information. Similar issues might exist for other special mappings. - Mappings like uprobe are not covered by the dynamic linker, and there is no effective solution for them. This feature's security enhancements will benefit ChromeOS, Android, and other high security systems. Testing: This feature was tested on ChromeOS and Android for both x86-64 and ARM64. - Enable sealing and verify vdso/vvar, sigpage, vector are sealed properly, i.e. "sl" shown in the smaps for those mappings, and mremap is blocked. - Passing various automation tests (e.g. pre-checkin) on ChromeOS and Android to ensure the sealing doesn't affect the functionality of Chromebook and Android phone. I also tested the feature on Ubuntu on x86-64: - With config disabled, vdso/vvar is not sealed, - with config enabled, vdso/vvar is sealed, and booting up Ubuntu is OK, normal operations such as browsing the web, open/edit doc are OK. Link: https://lore.kernel.org/all/20240415163527.626541-1-jeffxu@chromium.org/ [1] Link: Documentation/userspace-api/mseal.rst [2] Link: https://lore.kernel.org/all/CABi2SkU9BRUnqf70-nksuMCQ+yyiWjo3fM4XkRkL-NrCZxYAyg@mail.gmail.com/ [3] Link: https://lore.kernel.org/all/CABi2SkV6JJwJeviDLsq9N4ONvQ=EFANsiWkgiEOjyT9TQSt+HA@mail.gmail.com/ [4] Link: https://lore.kernel.org/all/202502251035.239B85A93@keescook/ [5] This patch (of 7): Provide infrastructure to mseal system mappings. Establish two kernel configs (CONFIG_MSEAL_SYSTEM_MAPPINGS, ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS) and VM_SEALED_SYSMAP macro for future patches. Link: https://lkml.kernel.org/r/20250305021711.3867874-1-jeffxu@google.com Link: https://lkml.kernel.org/r/20250305021711.3867874-2-jeffxu@google.com Signed-off-by: Jeff Xu Reviewed-by: Kees Cook Reviewed-by: Liam R. Howlett Reviewed-by: Lorenzo Stoakes Cc: Adhemerval Zanella Cc: Alexander Mikhalitsyn Cc: Alexey Dobriyan Cc: Andrei Vagin Cc: Anna-Maria Behnsen Cc: Ard Biesheuvel Cc: Benjamin Berg Cc: Christoph Hellwig Cc: Dave Hansen Cc: David Rientjes Cc: David S. Miller Cc: Elliot Hughes Cc: Florian Faineli Cc: Greg Ungerer Cc: Guenter Roeck Cc: Heiko Carstens Cc: Helge Deller Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Ingo Molnar Cc: Jann Horn Cc: Jason A. Donenfeld Cc: Johannes Berg Cc: Jorge Lucangeli Obes Cc: Linus Waleij Cc: Mark Rutland Cc: Matthew Wilcow (Oracle) Cc: Michael Ellerman Cc: Michal Hocko Cc: Miguel Ojeda Cc: Mike Rapoport Cc: Oleg Nesterov Cc: Pedro Falcato Cc: Peter Xu Cc: Randy Dunlap Cc: Stephen Röttger Cc: Thomas Weißschuh Cc: Vlastimil Babka Signed-off-by: Andrew Morton

ARM: 9443/1: Require linker to support KEEP within OVERLAY for DCE

2025-03-26T13:31:47Z

ld.lld prior to 21.0.0 does not support using the KEEP keyword within an overlay description, which may be needed to avoid discarding necessary sections within an overlay with '--gc-sections', which can be enabled for the kernel via CONFIG_LD_DEAD_CODE_DATA_ELIMINATION. Disallow CONFIG_LD_DEAD_CODE_DATA_ELIMINATION without support for KEEP within OVERLAY and introduce a macro, OVERLAY_KEEP, that can be used to conditionally add KEEP when it is properly supported to avoid breaking old versions of ld.lld. Cc: stable@vger.kernel.org Link: https://github.com/llvm/llvm-project/commit/381599f1fe973afad3094e55ec99b1620dba7d8c Reviewed-by: Linus Walleij Signed-off-by: Nathan Chancellor Signed-off-by: Russell King (Oracle)

Merge tag 'x86-core-2025-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2025-03-25T05:06:11Z

Pull core x86 updates from Ingo Molnar: "x86 CPU features support: - Generate the header based on build config (H. Peter Anvin, Xin Li) - x86 CPUID parsing updates and fixes (Ahmed S. Darwish) - Introduce the 'setcpuid=' boot parameter (Brendan Jackman) - Enable modifying CPU bug flags with '{clear,set}puid=' (Brendan Jackman) - Utilize CPU-type for CPU matching (Pawan Gupta) - Warn about unmet CPU feature dependencies (Sohil Mehta) - Prepare for new Intel Family numbers (Sohil Mehta) Percpu code: - Standardize & reorganize the x86 percpu layout and related cleanups (Brian Gerst) - Convert the stackprotector canary to a regular percpu variable (Brian Gerst) - Add a percpu subsection for cache hot data (Brian Gerst) - Unify __pcpu_op{1,2}_N() macros to __pcpu_op_N() (Uros Bizjak) - Construct __percpu_seg_override from __percpu_seg (Uros Bizjak) MM: - Add support for broadcast TLB invalidation using AMD's INVLPGB instruction (Rik van Riel) - Rework ROX cache to avoid writable copy (Mike Rapoport) - PAT: restore large ROX pages after fragmentation (Kirill A. Shutemov, Mike Rapoport) - Make memremap(MEMREMAP_WB) map memory as encrypted by default (Kirill A. Shutemov) - Robustify page table initialization (Kirill A. Shutemov) - Fix flush_tlb_range() when used for zapping normal PMDs (Jann Horn) - Clear _PAGE_DIRTY for kernel mappings when we clear _PAGE_RW (Matthew Wilcox) KASLR: - x86/kaslr: Reduce KASLR entropy on most x86 systems, to support PCI BAR space beyond the 10TiB region (CONFIG_PCI_P2PDMA=y) (Balbir Singh) CPU bugs: - Implement FineIBT-BHI mitigation (Peter Zijlstra) - speculation: Simplify and make CALL_NOSPEC consistent (Pawan Gupta) - speculation: Add a conditional CS prefix to CALL_NOSPEC (Pawan Gupta) - RFDS: Exclude P-only parts from the RFDS affected list (Pawan Gupta) System calls: - Break up entry/common.c (Brian Gerst) - Move sysctls into arch/x86 (Joel Granados) Intel LAM support updates: (Maciej Wieczor-Retman) - selftests/lam: Move cpu_has_la57() to use cpuinfo flag - selftests/lam: Skip test if LAM is disabled - selftests/lam: Test get_user() LAM pointer handling AMD SMN access updates: - Add SMN offsets to exclusive region access (Mario Limonciello) - Add support for debugfs access to SMN registers (Mario Limonciello) - Have HSMP use SMN through AMD_NODE (Yazen Ghannam) Power management updates: (Patryk Wlazlyn) - Allow calling mwait_play_dead with an arbitrary hint - ACPI/processor_idle: Add FFH state handling - intel_idle: Provide the default enter_dead() handler - Eliminate mwait_play_dead_cpuid_hint() Build system: - Raise the minimum GCC version to 8.1 (Brian Gerst) - Raise the minimum LLVM version to 15.0.0 (Nathan Chancellor) Kconfig: (Arnd Bergmann) - Add cmpxchg8b support back to Geode CPUs - Drop 32-bit "bigsmp" machine support - Rework CONFIG_GENERIC_CPU compiler flags - Drop configuration options for early 64-bit CPUs - Remove CONFIG_HIGHMEM64G support - Drop CONFIG_SWIOTLB for PAE - Drop support for CONFIG_HIGHPTE - Document CONFIG_X86_INTEL_MID as 64-bit-only - Remove old STA2x11 support - Only allow CONFIG_EISA for 32-bit Headers: - Replace __ASSEMBLY__ with __ASSEMBLER__ in UAPI and non-UAPI headers (Thomas Huth) Assembly code & machine code patching: - x86/alternatives: Simplify alternative_call() interface (Josh Poimboeuf) - x86/alternatives: Simplify callthunk patching (Peter Zijlstra) - KVM: VMX: Use named operands in inline asm (Josh Poimboeuf) - x86/hyperv: Use named operands in inline asm (Josh Poimboeuf) - x86/traps: Cleanup and robustify decode_bug() (Peter Zijlstra) - x86/kexec: Merge x86_32 and x86_64 code using macros from (Uros Bizjak) - Use named operands in inline asm (Uros Bizjak) - Improve performance by using asm_inline() for atomic locking instructions (Uros Bizjak) Earlyprintk: - Harden early_serial (Peter Zijlstra) NMI handler: - Add an emergency handler in nmi_desc & use it in nmi_shootdown_cpus() (Waiman Long) Miscellaneous fixes and cleanups: - by Ahmed S. Darwish, Andy Shevchenko, Ard Biesheuvel, Artem Bityutskiy, Borislav Petkov, Brendan Jackman, Brian Gerst, Dan Carpenter, Dr. David Alan Gilbert, H. Peter Anvin, Ingo Molnar, Josh Poimboeuf, Kevin Brodsky, Mike Rapoport, Lukas Bulwahn, Maciej Wieczor-Retman, Max Grobecker, Patryk Wlazlyn, Pawan Gupta, Peter Zijlstra, Philip Redkin, Qasim Ijaz, Rik van Riel, Thomas Gleixner, Thorsten Blum, Tom Lendacky, Tony Luck, Uros Bizjak, Vitaly Kuznetsov, Xin Li, liuye" * tag 'x86-core-2025-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (211 commits) zstd: Increase DYNAMIC_BMI2 GCC version cutoff from 4.8 to 11.0 to work around compiler segfault x86/asm: Make asm export of __ref_stack_chk_guard unconditional x86/mm: Only do broadcast flush from reclaim if pages were unmapped perf/x86/intel, x86/cpu: Replace Pentium 4 model checks with VFM ones perf/x86/intel, x86/cpu: Simplify Intel PMU initialization x86/headers: Replace __ASSEMBLY__ with __ASSEMBLER__ in non-UAPI headers x86/headers: Replace __ASSEMBLY__ with __ASSEMBLER__ in UAPI headers x86/locking/atomic: Improve performance by using asm_inline() for atomic locking instructions x86/asm: Use asm_inline() instead of asm() in clwb() x86/asm: Use CLFLUSHOPT and CLWB mnemonics in x86/hweight: Use asm_inline() instead of asm() x86/hweight: Use ASM_CALL_CONSTRAINT in inline asm() x86/hweight: Use named operands in inline asm() x86/stackprotector/64: Only export __ref_stack_chk_guard on CONFIG_SMP x86/head/64: Avoid Clang < 17 stack protector in startup code x86/kexec: Merge x86_32 and x86_64 code using macros from x86/runtime-const: Add the RUNTIME_CONST_PTR assembly macro x86/cpu/intel: Limit the non-architectural constant_tsc model checks x86/mm/pat: Replace Intel x86_model checks with VFM ones x86/cpu/intel: Fix fast string initialization for extended Families ...

Merge tag 'rcu-next-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux

2025-03-25T02:41:37Z

Pull RCU updates from Boqun Feng: "Documentation: - Add broken-timing possibility to stallwarn.rst - Improve discussion of this_cpu_ptr(), add raw_cpu_ptr() - Document self-propagating callbacks - Point call_srcu() to call_rcu() for detailed memory ordering - Add CONFIG_RCU_LAZY delays to call_rcu() kernel-doc header - Clarify RCU_LAZY and RCU_LAZY_DEFAULT_OFF help text - Remove references to old grace-period-wait primitives srcu: - Introduce srcu_read_{un,}lock_fast(), which is similar to srcu_read_{un,}lock_lite(): avoid smp_mb()s in lock and unlock at the cost of calling synchronize_rcu() in synchronize_srcu() Moreover, by returning the percpu offset of the counter at srcu_read_lock_fast() time, srcu_read_unlock_fast() can avoid extra pointer dereferencing, which makes it faster than srcu_read_{un,}lock_lite() srcu_read_{un,}lock_fast() are intended to replace rcu_read_{un,}lock_trace() if possible RCU torture: - Add get_torture_init_jiffies() to return the start time of the test - Add a test_boost_holdoff module parameter to allow delaying boosting tests when building rcutorture as built-in - Add grace period sequence number logging at the beginning and end of failure/close-call results - Switch to hexadecimal for the expedited grace period sequence number in the rcu_exp_grace_period trace point - Make cur_ops->format_gp_seqs take buffer length - Move RCU_TORTURE_TEST_{CHK_RDR_STATE,LOG_CPU} to bool - Complain when invalid SRCU reader_flavor is specified - Add FORCE_NEED_SRCU_NMI_SAFE Kconfig for testing, which forces SRCU uses atomics even when percpu ops are NMI safe, and use the Kconfig for SRCU lockdep testing Misc: - Split rcu_report_exp_cpu_mult() mask parameter and use for tracing - Remove READ_ONCE() for rdp->gpwrap access in __note_gp_changes() - Fix get_state_synchronize_rcu_full() GP-start detection - Move RCU Tasks self-tests to core_initcall() - Print segment lengths in show_rcu_nocb_gp_state() - Make RCU watch ct_kernel_exit_state() warning - Flush console log from kernel_power_off() - rcutorture: Allow a negative value for nfakewriters - rcu: Update TREE05.boot to test normal synchronize_rcu() - rcu: Use _full() API to debug synchronize_rcu() Make RCU handle PREEMPT_LAZY better: - Fix header guard for rcu_all_qs() - rcu: Rename PREEMPT_AUTO to PREEMPT_LAZY - Update __cond_resched comment about RCU quiescent states - Handle unstable rdp in rcu_read_unlock_strict() - Handle quiescent states for PREEMPT_RCU=n, PREEMPT_COUNT=y - osnoise: Provide quiescent states - Adjust rcutorture with possible PREEMPT_RCU=n && PREEMPT_COUNT=y combination - Limit PREEMPT_RCU configurations - Make rcutorture senario TREE07 and senario TREE10 use PREEMPT_LAZY=y" * tag 'rcu-next-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux: (59 commits) rcutorture: Make scenario TREE07 build CONFIG_PREEMPT_LAZY=y rcutorture: Make scenario TREE10 build CONFIG_PREEMPT_LAZY=y rcu: limit PREEMPT_RCU configurations rcutorture: Update ->extendables check for lazy preemption rcutorture: Update rcutorture_one_extend_check() for lazy preemption osnoise: provide quiescent states rcu: Use _full() API to debug synchronize_rcu() rcu: Update TREE05.boot to test normal synchronize_rcu() rcutorture: Allow a negative value for nfakewriters Flush console log from kernel_power_off() context_tracking: Make RCU watch ct_kernel_exit_state() warning rcu/nocb: Print segment lengths in show_rcu_nocb_gp_state() rcu-tasks: Move RCU Tasks self-tests to core_initcall() rcu: Fix get_state_synchronize_rcu_full() GP-start detection torture: Make SRCU lockdep testing use srcu_read_lock_nmisafe() srcu: Add FORCE_NEED_SRCU_NMI_SAFE Kconfig for testing rcutorture: Complain when invalid SRCU reader_flavor is specified rcutorture: Move RCU_TORTURE_TEST_{CHK_RDR_STATE,LOG_CPU} to bool rcutorture: Make cur_ops->format_gp_seqs take buffer length rcutorture: Add ftrace-compatible timestamp to GP# failure/close-call output ...